Speed controlling mechanism for



Feb. 10, 1959 s. A. MONK ET AL 2,

' SPEED CONTROLLING MECHANISM FOR STRAIGHT-BAR KNITTING MACHINES Filed March 5, 1956 n a a j I 6 Q 5 J I 8i 6? 00 I I n q I w 5: W a L: 13

N Fa m ,9, a a L l H, Q

m N \Q J 4 Inventor! y%IMh,/ u

M W Attorneys United States Patent" SPEED CONTROLLING MECHANISM FOR STRAIGHT-BAR KNITTING MACHINES Samuel Arthur Monk, Gedling, and Dennis Matthews, Mansfield, England, assignors to S. A. Monk (Sutton in Ashfield) Limited, Sutton-in-Ashfield, England Application March 5, 1956, Serial No. 569,576 3 Claims. on. 66-82) This invention relates to improvements in the speed controlling mechanism of electrically driven straight-bar knittingm'achines, particularly straight-bar knitting machines for knitting garments or parts of garments. Machines for this purpose are adapted to shape the garments or parts thereof by both narrowing and widening as may be required from time to time. It has been proposed to provide a variable draw that is to vary the length of traverse of the slurcock bar in machines for knitting garments or parts thereof so that the length of the draw always corresponds to the length of the course knitted. It will be seen that in machines in which the slurcock bar is driven by 'a draw lever and cam, if the speed of the machine remains constant the speed of the draw will decrease as the width of the work decreases as whatever the length of the draw, it takes place during the same angular movement of the draw cam. It will therefore be seen that to maintain a constant speed of draw the speed of the machine should be increased as the draw is shortened and vice versa. The object of the present invention is to provide automatic means for increasing the speed of the machine as the draw is shortened and vice versa whilst providing for reducing the speed of the machine during a. fashioning operation and for stopping, starting or reducing the speed of the machine at any time by means of the manually operated control normally provided.

According to this invention the speed of the driving motor of the machine is controlled by a shaft which is rotated in one direction to increase the speed of the motor and in the reverse direction to reduce the speed of the motor and the shaft is turned by a toothed member such as a rack or quadrant which engages with a pinion on the shaft, the rack or quadrant being moved by connecting it to a part of the machine which is adjusted when any adjustment is made of the length of the draw and is arranged to move the rack or quadrant to increase the speed of the motor as the draw decreases in length and vice versa. Provision is also made to move the rack or quadrant by means of the manually operated control shaft to stop, start or reduce the speed of the machine at any time and also to move-the rack or quadrant to reduce the speed of the machine when a fashioning motion is to be carried out.

The invention will now be more particularly described with reference to the accompanying drawing which shows motor speed control mechanism constructed according to this invention for the driving motor of a straight-bar knitting machine. Only suflicient of the straight-bar knitting machine is shown in the drawing as is necessary to enable the invention to be understood.

The speed of the electric motors normally used for driving straight-bar knitting machines is varied by adjusting the position of the brush gear to shift the brushes and the adjustment is made by rotating a shaft mounted in hearings on the motor casing 11 and provided for this purpose. In carrying out this invention a pinion '12 is secured on this control shaft 10 and gears with the 2,872,797 Patented Feb. 10, 1959 teeth of a rack or preferably as shown in the drawing a quadrant 13 which may conveniently be pivoted on the ice - shaft 14 carried by the motor casing 11. A pin 15 is provided on the quadrant 13 and this pin 15 engages in a slot 16 in a link 17 connected to one arm 18 of a bell crank lever pivoted at 19 to the machine frame. The pin 15 is normally held up to the inner end of the slot 16 that is the end which is nearest to the end of the link connected to the arm 18 of the bell crank lever, by means of a spring 20 connected between the quadrant 13 and a convenient point on the machine frame. The spring 20 is connected to the quadrant 13 so that its action is to move the quadrant 13 in a direction which will turn. the control shaft 10 to increase the speed of the motor and consequently the speed of the machine.

The other arm 21 of the bell crank lever is connected by a link 22 to a lever 23, pivoted at 24 to the machine frame and having its other end connected by a pin and slot connection to a part 25 of the machine which is adjusted with the draw and arranged so that the draw is reduced the slotted link 17 is drawn in a direction duces the speed of the motor.

away from the pin 15 in the quadrant 13. Owing to the action of the spring 20 the quadrant 13 will follow the link 17 and turn the control shaft It) so that as the draw is reduced in length so the speed of the motor will be increased. As the length of the draw is increased the opposite effect will be obtained and the link 17 will move the quadrant-against the action of the spring 20 to reduce the speed of the motor as the length of the draw increases.

In order to move the lever 23 to adjust the position of the link 17 it may be connected to the carrier stop boxes or to a nut on the narrowing or carrier screw so as to be moved when the narrowing or carrier screw is adjusted when the draw is altered. When however the thread carrier bars of the machine are driven in well known manner by a driver carried by a flexible member such as a pair of chains which pass round sprockets on saddles which are adjustable towards and away from each other to alter the traverse of the thread carriers, then the lever 23 which adjusts the slotted link 17 may conveniently be connected to one of the saddles to be moved when the saddle moves and arranged so that as the saddle is moved inwards to reduce the width of the work the speed of the motor is increased and as the saddle moves outwards to widen the work the speed of the motor is reduced.

In order to reduce the speed of the motor during a fashioning motion of the machine the following arrangement is adopted. Disposed on the quadrant pivot shaft 14 is an arm 26. This arm 26 is loosely mounted at one end on the pivot shaft 14 and its other end is con nected by a link 27 to a lever 28 which is actuated through the follower 29 by a cam 30 on the mainshaft 31 of the machine when the mainshaft 31 is engaged to bring the fashioning cams into action. The follower 29 is held in engagement with the cam 30 by a spring 32 and the cam 30 is so shaped that the lever 28 moves the arm 26 into engagement with the pin 15 on the quadrant 13 and moves the quadrant against the action of the spring 20 and re- It will be understood that the spring 32 is made strong enough to overcome the normal action of the spring 20. When the arm 26 engages with and moves the pin 15, the latter moves along the slot 16 in the link 17 towards the outer end of the slot 16. The shape of the cam 39 is arranged so that the quadrant 13 is moved to a position where the correct motor speed for a fashioning motion is provided.

Disposed on the qaudrant pivot shaft 14 is a second arm 33 which is connected with the manually operated control shaft 34 and is moved thereby to engage with the pin 15 on the quadrant 13 to move the latter to slow When the control shaft 34 i the control shaft 34 has a pinion 35 secured thereon which 1 engages with the teeth of a quadrant 36 pivoted on the shaft 37. The quardant 36 is connected by alink 38 with the arm 33 so that the latter is moved in one direction or the other by turning the control shaft 34 in the appropriate direction It will be seen that the position of the slotted link 17 controls the maximumspeed of the machine at any time during knitting so that' -the machine cannot be over run by moving the manually operated control to its maximum speed position. Similarly the maximum speed of the machine during a fashioning motion is controlled by the cam 30, lever 28 and arm 26 but the manual control shaft 34 can be operated at any time to stop and start the machine.

What we claim is:

1. Motor speed control mechanism for a straight-bar knittingmachine comprising a motor speed control shaft, a pinion thereon, a toothed member engaging therewith, a pin on the toothed member, a longitudinally movablemember connected to a part of the machine which ismanually operated speed control shaft and a second arm engageable with the pin and means to move said second arm to move the pin to or prevent its movement beyond apredetermined position'when the machine is carrying out a fashioning operation.

2. Motor speed control mechanism according to claim 1 in which the means to move the said second arm comprises a lever, a link connecting the lever to the arm, a follower on the lever and a cam on the mainshaft to engage with the follower.

3. Motor speed'control mechanism for a straight-bar knitting machine comprising a motor speed control shaft, a pinion thereon, a toothed member engaging therewith, a pin on the toothed member and engaging in a longitudinal slot in a longitudinally movable member connected to a part of the machine which is moved when the length of the draw is altered, a spring to normally hold the pin in engagement with the inner end of the slot, an arm engaging with the pin, an operative connection between the arm and a manually operated speed control shaft and a second arm engageable with the pin and means to. move, the said. second-arm to movethe pinto or prevent its movement beyond a predetermined position when the machine is carrying out a fashioning operation.

References Cited in the file of this patent UNITED STATES PATENTS v 2,571,314 Vaclavik Oct. 16, i 

